Hello
My question is about Kindle Touch
Is there a maximum number of characters that can be exported to the PC by one highlighted part or a limit on the maximum number of highlighted parts to be exported per document? My Sony-PRS-T1 has restrictions like these, that's why I'm asking (btw my question is about non-DRM books.

I suspect they have a size limit for copyright purposes. Otherwise a person could copy the entire text of a book at one time and send it to their computer, which would totally negate the reason for having DRM. Publishers would probably get upset if Amazon allowed really large chunks of text to be copied at one time.

Hello
My question is about Kindle Touch
Is there a maximum number of characters that can be exported to the PC by one highlighted part or a limit on the maximum number of highlighted parts to be exported per document? My Sony-PRS-T1 has restrictions like these, that's why I'm asking (btw my question is about non-DRM books.

It's a per-book limit. If you use the tools to strip the DRM from Kindle ebooks, the clipping limit gets removed too.